Top 3 API Testing Tool Comparison: SoapUI vs Postman, Katalon Studio

To implement API testing successfully, teams must have a good set of tools that match specific requirements. This article presents a comparison of the top three popular tools for API testing: SoapUI, Postman, and Katalon Studio in order to help you decide which tools work best for your API automation tests. SoapUI and Postman specialize in API testing while Katalon Studio provides a complete solution for API, Web, and mobile app testing.

SoapUI

SoapUI is widely cited as a top choice when it comes to API testing. It is a headless functional testing tool specifically designed for API testing. SoapUI supports both REST and SOAP services. API automation testers can either use open-source or pro versions. The pro edition has a user-friendly interface and several advanced features such as assertion wizard, form editor, and SQL query builder. SoapUI is a tool of ReadyAPI suite, offered by SmartBear.

The tool provides many advanced features for API testing, including

Generates tests easily using drag and drop, point-and-click

Powerful data-driven testing with data from files and databases

Scripts can be reused easily

Mocks services with RESTful mocking

Asynchronous testing

SoapUI is distributed as Open-source and Pro versions ($659/year for medium and large teams).

Postman

Postman emerged as a popular automation tool for API testing after having only been known as a browser extension for API validation. Postman can be installed as a browser extension or a desktop application on Mac, Linux, and Windows. It is used not only by automation testers for API tests but also by developers for developing and validating APIs. It has evolved, in fact, as an environment to develop and test APIs. Some notable features include:

A comprehensive feature set for designing, debugging, testing, documenting, and publishing APIs

Supports both automated and exploratory testing

A friendly and easy-to-use user interface

Accepts Swagger and RAML API formats

Postman is affordable as the product is offered in three editions: Postman (free), Postman Pro ($8/month), and Postman Enterprise ($21/month).

Katalon Studio

Katalon Studio is an integrated environment to generate and execute API, Web-based GUI, and mobile apps automation tests. It has a rich feature set for these types of testing and supports multiple platforms including Windows, Mac OS, and Linux. By integrating Selenium and Appium engines with all needed components, built-in keywords, and templates, Katalon Studio provides a unique environment for both testers and developers to perform API and Web automation tests. Some notable highlights of the tool:

Summary

This article provides a review of 3 popular and promising tools for API test automation by comparing SoapUI vs Postman and Katalon Studio. Each tool has its own pros and cons, but they are widely used by developers and testers for their API testings. (Read more Best API Testing Tools for REST & SOAP Services)